In a typical hard disk drive (HDD), servo sectors on the disk are used to provide position information about the location of a magnetic head over a disk surface. A one approach for writing such servo information on a disk surface of an HDD is referred to as spiral-based self-servo writing, or spiral-based SSW. According to this approach, multiple spiral-shaped servo information patterns (or “servo spirals”) are written on at least one disk surface prior to the SSW process. During the SSW process, each magnetic head of the HDD is positioned relative to a disk surface based on the servo spirals, so that the final servo information (the servo sectors) can be written on the disk surface by the magnetic head.
Ideally, the servo sectors written on a disk surface during an SSW process are equally spaced on the disk surface in the radial direction, so that data track pitch, i.e., the radial spacing between each data track, is substantially the same across the entire disk surface. This is because variable data track pitch on different regions of a disk surface can cause data integrity problems and/or reduce HDD performance. Unfortunately, data track pitch is strongly affected by the slope of the servo spirals used to position the magnetic head while writing the data track servo sectors, and the servo spirals typically employed in the SSW process commonly include portions that vary significantly from the ideal servo spiral shape. Consequently, data track servo sectors can be written on a disk surface with unwanted variation in data track pitch. Accordingly, there is a need in the art for systems and methods of generating servo sectors on a disk surface of an HDD with more uniform data track pitch.